Perhaps the biggest diplomatic development in Asia in recent weeks was an agreement between South Korea and China, in which both countries said they will try to put their estranged relationship "back on a normal track."

This will end the yearlong acrimony over South Korea's installation of an American missile defense system ― the Terminal High Altitude Area Defense (THAAD) ― that precipitated China's massive economic retaliation, costing the Korean economy over $7.5 billion.

China continues to oppose the deployment of THAAD. Beijing maintained from the beginning that the missile defense system with intrusive radar undermines China's sovereign security. Yet China seems to have decided to live with the one THAAD battery deployed in Seongju, South Korea, which Seoul and Washington repeatedly said was only for deterrence against the North Korean nuclear/missile threat.

China's modified position must have been influenced by South Korea's "position" or "pledge" for "three No's": no additional THAAD deployment, no participation in the construct of a U.S.-led regional missile defense network and no collaboration for a trilateral military alliance including Japan. In fact, the South Korean foreign minister told the national parliament that the Moon government was not seeking any of the three possible paths, which the Chinese are concerned about.

China's decision may also have been influenced by the reemergence of Xi Jinping's consolidated power, the strongest since Mao Zedong, coming out of the twice a decade Communist Party Congress, which signaled China's more aggressive search for global leadership in competition with the United States.

President Moon is scheduled to meet Xi on the sidelines of the APEC summit in Da Nang, Vietnam, later this week. And President Trump visits Seoul after the breakthrough in the deadlock of relations with China. Moon is re-embarking on a treacherous path to a balancing act between two superpowers. As Trump says, every nation puts their interests first. Moon must seek what's best for Korea, but without weakening the alliance with the U.S.

On the economic side, the rapprochement with China is seen as a positive development. South Korea, with its trade with China surpassing its trade with the U.S. and Japan combined, will again be able to sell more goods and entertainment programs to China. More Chinese tourists will come to Korea and buy products from Korean department stores, the numbers of which had been curtailed by 60 percent as a result of the Chinese government's interference.

On the security and political side, there is a mixed view of hope and concern. To seek a peaceful resolution of the North Korean nuclear issue, normalized ties with Beijing would be helpful, especially at a time when China has become more displeased with North Korean provocations at the cost of face to China.

The Moon government is being criticized for "agreeing on the three No's" by the opposition parties for giving up future security options and surrendering to China, which does not apologize or even recognize its economic retaliation against the South. The major opposition party still supports redeployment of tactical nuclear weapons or Seoul's own nuclear armament.

The Trump administration still believes China can fix the nuclear problem, if it really wants to. Not a sure thing. Even surrogates of Trump's belligerent rhetoric believe it is directed at the Chinese, to warn them, "If you don't do more, we will have to use military force." The problem with the threat of military action is that it scares more South Koreans and Americans than it does the Chinese or North Koreans.

On the other hand, if Moon is inclined to appease China, it might affect the alliance with the U.S., whereas the South needs a strong allied deterrence without which the South is neither safe nor can any dialogue succeed. In addition, there is a broader question of how the U.S.-China relations of rivalry will play out in the end.

Trump is not a traditional American leader, assisted by two competing schools of thought ― America-first economic nationalists and more traditional foreign policy minds. The question is who is this president who tweets his own ideas, and who will listen to him when it comes to the issue of the Korean Peninsula and on an overall Asia policy.

Despite Seoul's position of no trilateral alliance, the military leaders of South Korea, Japan and the U.S. are maintaining their periodic meetings to coordinate training and deterrence measures against the threat of North Korean nuclear missiles. In the meantime, Seoul and Beijing resumed defense ministerial talks. South Korea is expected to explain the defensive nature of the U.S. missile system installed in the South.

We hope that Trump's 12-day Asia visit will contribute to promoting peace and prosperity for all. What's your take?

Tong Kim (tong.kim8@yahoo.com) is a Washington correspondent and columnist for The Korea Times. He is also a fellow at the Institute of Korean-American Studies.